Photographic diazo-sensitized glassine paper



March 28, 1950 w. D. PETERSON 2,501,874

PHOTOGRAPHIC DIAZO-SENSITIZED GLASSINE PAPER Fi led June 12', 1946 DOPE NO DOPE OVERFLOWS FROM NOZZLE TO PAN TENSION ROLLS DOP GLASSINE PAPER BASE TAKE UP ROLL DOPE RECIRCULATED FROM PAN TO NOZZLE INVENTOR. W/LLARD D. PETERSON I T TORNEVS Patented Mar. 28, 1950 UNITED STATES PATENT OFFICE rno'rocnnrnro DIAZO-SENSITIZED GLASSINE PAPER Will'ardD. Peterson; Easton, Pa., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Application June 12, 1946, Serial No. 676,224

The present invention relates to the manufacture of photographic diazotype materials having particular utility in the preparation of intermediate or transition prints and more particularly to the base of such diazotype materials to which the sensitizing composition is applied.

The diazotype process, which is of rather general application in the formation of prints from original patterns, has become increasingly more importantin the preparation of transition prints or intermediate prints on a transparent base stock for the purpose of reproducing drawings, or ginals of old manuscripts and the like. The efiiciency of these prints depends upon a number of factors, to wit, the opacity of the azo dye image formed to ultraviolet light, the transparency of the background, the speed at which the intermediate print may be reproduced, and the like.

There are on the market 'at the present time, photographic diazotype materials which yield valuable transition or intermediate prints. These diazotype materials are prepared with a transparent support such as transparentized paper, i. e., rag paper, cellulose esters such as cellulose acetate, and the like. These diazotype materials, however, do not represent the ultimate from a practical standpoint, particularly as regards contrast, line density, speed of duplication and the like.

It has now been discovered that photographic diazotype materials for the preparation of transition or intermediate prints which are far superior to those now available *on the market, can be obtained by utilizing as the base to which the sensitizing compositions are applied, a glassine paper stock. Not only do such diazotype materials prepared with 'the glassine paper base provide very high contrast between the opacity of the dye image as compared with the high transparency of the support permitting-the production of a very high contrast print, but in addition the line density of the prints obtained therewith is excellent, and the speed with which duplicates can be obtained is markedly increased. As a matter of fact, with the diazotype materials contemplated herein; reprints oan be made from the glassine intermediates at least twenty per cent faster than it ispossihle to produce :reprints from the presently available transparent paper diazotype materials.

It is accordingly an object of the presentinvention to prepare photographic diazotype materials while utilizing glassine paper as the base.

It is a further object of the present invention to provide transparent photographic diazotype materials while utilizing gla-ssine paper asthe support and while including in the sensitizing composition a small amount of an organic film forming material.

It is a further object of the present invention 2 Claims.

to provide transparent photographic diazotype materials particularly suitable for the production of intermediate or transition prints while utilizing glassine paper as the base and while coating both sides of such base with the sensitizing composition containing a small amount of an organic film forming material.

A further object of the present invention is to produce photographic diazotype materials having a glassine paper base, said materials having the ability to permit duplication at a much greater rate than any materials of a like nature presently known.

Other and further important objects of the invention will become apparent as the description proceeds.

The glassine paper which is to serve as the base is commercially available and may be prepared according to, for example, U. S. P. 1,914,798 and 1,914,799. While different weights of paper may be used for the preparation of the lightsensitivematerials, I have discovered that best results are obtained when utilizing a 25-pound weight paper (500 sheets, 24 by 36 inches).

Glassine paper in and of itself is not particularly strong. It is therefore preferable to incorporate in the coating composition an organic film forming material to thereby increase the strength of the base. Any organic film forming material, either water-insoluble or Water-soluble may be employed, so long as it is transparent in a thin layer such as a layer having a thickness of .01 inch or less. Film forming materials which meet this requirement are known and are available on the open market. For example, suitable water-insolublefilm forming materials are: polystyrene, polyacrylic acid esters such as the methyl or ethyl ester, polymethacrylic acid ester such as the methyl or ethyl ester, the copolymers of vinyl chloride and a vinyl ester such as vinyl acetate, copolymers of maleic anhydride and styrene, copolymers of vinylidine chloride and vinyl acetate, alkyd resins such as those derived from phthalic acid and glycerol, phthalic acid and sorbitol, phthalic acid, glycerol and a drying oil, such as poppyseed oil, cellulose esters such as cellulose acetate, cellulose acetate-butyrate, cellulose propionate, cellulose acetate-propionate, linear superpolymers such as linear superpolyamides, linear superpolyurethanes, linear superpolyureas and the like. As examples of organic film forming materials which are soluble in water, reference may be made to polyvinyl alcohol,

, incompletely condensed and polymerized urea formaldehyde resins, etc.

Where the resinous organic film forming material is water insoluble, the sensitizing composition containing'such material is applied from a solution of the ingredients in an organic solvent.

For this purpose one may utilize the commonly known resin solvents such as acetone, butyl acetate, benzyl alcohol, butyl alcohol, mixtures of ethers and alcohols such as a mixture of ethanol and ethyl ether, chlorinated hydrocarbons such as chloroform, ethylene chloride, and mixtures of such chlorinated hydrocarbons with alcohols or ethers such as ethylene chloride and butyl chloride and diethyl ether and the like. Inasmuch as the resins involved are old products, it is a relatively simple matter by a reference to the literature, to select the desired solvents for use with any particular resin.

It has been ascertained that by including the resinous organic film forming material in the coating composition, not only the strength of the glassine paper is materially increased but that other valuable characteristics are bestowed upon observed that the glassine paper base has a tendency to curl. This tendency, however, can be counteracted by applying the sensitizing composition to both faces of the base, preferably at the same time. Rather peculiarly, if a difierent resin is utilized for coating one face of the base than is employed for coating the other, the aforenoted tendency to curl is not obviated. This difficulty is obviated if a resin is applied to the back of the base and the same resin containing the sensitizing composition is applied to the front of the base. It is therefore of the greatest importance when applying the compositions, to both surfaces of the base, to utilize the same resin in each instance.

The light-sensitive diazonium compounds employed in the sensitizing composition are those generally utilized in the manufacture of diazotype papers but are preferably of the class of the paraphenylene diamines. As examples of light-sensitive diazonium compounds which I have found to be suitable for my purpose, mention may be made of the following:

p-Diethylaminobenzene diazonium chloride 2.5.4-triethoxydiphenyl-4-diazonium acid sulfate the diazonium compounds from p-(N-hydroxyethyl-N-methylamino) -aniline 1 p-Amino-diphenylamine 4ediethylamino-o-phenetidine 4-benzoylamino-2.5-diethoxyaniline .p-Diethylaminoaniline p-Dimethylaminoaniline p- (N-benzyl-N-ethyl) -aniline p-Di- (fi-hydroxyethyl) -amino-aniline p-Ethylamino-m-toluidine p-(N-ethyl-N-,3-hydroxyethylamino) o toluidine p-Di- (B-hydroxyethyl) -amino-o-chloro-aniline p-Ethylaminoaniline p-Phenylenediamine It is recognized in the art that in the preparation of transparent diazotype materials which alcohol, ethylene chloride and propanol, ethylene are to be used for making intermediate and transition prints, a coupling component should be selected which'will yield a dyestufi image which has a sepia or yellow tone. Examples of such coupling components are the phenols, particularly the polyhydric phenols and their derivatives, such as resorcinol, resorcinol monoand disulfonic acids, phenol itself, 2- (omega-phenylamino) -methyl-l-hydroxybenzene, p (2 hydroxyphenyD-propionic acid, and similar compounds referred to in U. S. P. 2,245,628, 2.7-dihydroxynaphthalene (U. S. P. 1,758,676) phloroglucinol and the like.

Such coupling components will hereinafter be referred to as phenolic coupling components capable of yielding with the usual diazos, azo dyestuff images having a yellow or sepia tone.

The sensitizing compositions may contain the usual adjuncts such as metal salts, to intensify the dyestuif image, i. e., aluminum sulfate, titanium ammonium fluoride, nickel sulfate and the like, stabilizing agents such as thiourea, thiosinamine, naphthalene trisulfonic acid and the like, acids designed to retard precoupling such as citric acid, maleic acid, tartaric acid, boric acid and the like, hygroscopic agents such as glycol, glycerin, dextrin and the like. Such agents and their utilization in the stated relationship are so well known in this art that further details with regard thereto need not be given.

In making up the sensitizing compositions, one uses the amounts of diazo compound, coupling component and the other usual adjuncts customary in the art. If desired, however, one may also employ a slight excess of the diazo and coupling component although as ageneral rule this is unnecessary. The quantity of the resin which is to be employed will vary from about 5 to 20 per cent by weight of the composition and is preferably about 10 per cent. The quantity of the sensitizing composition which is applied to the base ranges from about 10 to 12 per cent by weight of the base.

An apparatus by which the sensitizing composition may be simultaneously applied to both faces of the base is shown diagrammatically in the accompanying drawing. In the drawing, the term dope is intended to signify the sensitizing composition containing the organic film forming material. Inasmuch as the drawing bears appropriate legends and is therefore self-explanatory, a description of the same herein is deemed to be unnecessary.

The following examples illustrate the invention, although it is to be understood that these are exemplary and not limitative.

Example 1 25-pound glassine paper is coated in an apparatus of the type shown in the drawing on both faces with a sensitizing composition having the following ingredients:

10 parts of low viscosity cellulose acetate 90 parts of acetone 2.5 parts of p-diethylamino benzene diazonium boron fluoride 2.1 parts of resorcinol 1.6 parts of maleic acid The resulting diazotype material, which is high- .ly transparent because of the base, yields, upon exposure toa pattern and development with ammonia, intermediate or transition prints of a very high contrast and a fine line density. While utilizing such print for copying, it is found that the print may be duplicated at a 20 to 30 per cent faster rate than is possible with the transparent diazotype materials presently available for the preparation of intermediate prints.

Example II Glassine paper prepared according to USP 1,914,798 or 1,914,799 is simultaneously coated on both faces with a composition prepared as follows:

.003 mol of resorcinol .0015 mol of para-diethylamino benzene diazonium boron fluoride 4 grams of maleic acid 0.5 gram of thiourea 5 cc. tri-ocresyl phosphate are dissolved in 20 cc. acetone cc. of absolute ethyl alcohol 15 cc. of absolute ethyl ether The resultin solution is then diluted to 100 cc. with a composition containing the following ingredients:

700 grams of cellulose acetate-butyrate (16% butyryl content) 3 liters of acetone The procedure is the same as in Example I excepting that there is employed in lieu of the cellulose acetate, polystyrene dissolved in methyl ethyl ketone or dioxane.

The photographic diazotype glassine papers referred to hereinabove have been described as particularly suitable for the preparation of transition or intermediate prints. It is to be pointed out, however, that such photographic diazotype papers have many other applications such as, for example, overlays used for multicolored prints, especially semi-transparent Wrappers, lamp-shades and the like. When so utilized, it is unnecessary to select coupling components which yield yellow or sepia toned azo dyes inasmuch as the question of ultraviolet light opacity is not of particular moment in these applications. Consequently, where the photographic diazotype glassine papers are so used, one may employ other couplers such as p-methyl-N-phenyl pyrazolone, the amide of a-resorcylic acid, the methyl amide of p-resorcylic 8 acid, 2-hydroxynaphtha1ene-3.6-disulfonic acid, the hydrochloride of 1-hydroxynaphthalene-7- .biguanidine, H acid, J acid, 2.3-dihydroxynaphthalene, 2.3-dihydroxynaphthalene-fi-carboxylic acid-and the like. For instance, prints of a blue shade may be obtained by replacing the resorcinol of Example I by an equivalent amount of 2.3-

dihgdroxynaphthalene. It is therefore to be understood that the invention in its broadest aspects contemplates photographic diazotype materials in which a sensitizing composition comprising a diaio component and an azo dyecoupling component are applied to a glassine paper base.

Various-modifications of the invention will become apparent to persons skilled in the art and I therefore do not intend to be limited in the patent granted except as required by the appended claims.

I claim: 1. Transparent diazotype materials particular- 1y suitable for the preparation of intermediate or transition prints comprising a glassine paper base having applied to both faces thereof a sensitiz ing composition comprising a light-sensitive diazo compound, a small quantity of a resinous low viscosity cellulose ester film forming material and a phenolic coupling component capable of yielding with the diazo compound anazo dye having atone selected from the class consisting of yellojw and sepia tones. V

2. Transparent diazotype materials particularly suitable for the production of transition and intermediate prints comprising a glassine paper base having applied to both surfaces thereof a sensitizing composition comprising a low viscosity cellulose acetate, p-diethylaminobenzene diazonium borofluoride and resorcinol.

WILLARD D. PETERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 328,431 Roche Oct. 13, 1885 656,751 Schwarz Aug. 28, 1900 1,756,400 Schmidt et al Apr. 29, 1930 1,964,358 Krieger June 26, 1934 2,239,704 De Boer et a1. Apr. 29, 1941 2,245,628 VonPoser et a1 June 17, 1941 2,246,425 VonPoser et a1. June 17, 1941 2,378,583 Schmidt et al. June 19, 1945 2,405,523 Sease et a1. Aug. 6, 1946 FOREIGN PATENTS Number Country Date 409,134 Great Britain Apr. 26, 1934 443,955 Great Britain Mar. 10, 1936 450,817 Great Britain July 24, 1936 536,714 Great Britain May 23, 1941 

1. TRANSPARENT DIAZOTYPE MATERIALS PARTICULARLY SUITABLE FOR THE PREPARATION OF INTERMEDIATE OR TRANSITION PRINTS COMPRISING A GLASSINE PAPER BASE HAVING APPLIED TO BOTH FACES THEREOF A SENSITIZING COMPOSITION COMPRISING A LIGHT-SENSITIVE DIAZO COMPOUND, A SMALL QUANTITY OF A RESINOUS LOW VISCOSITY CELLULOSE ESTER FILM FORMING MATERIAL AND A PHENOLIC COUPLING COMPONENT CAPABLE OF YIELDING WITH THE DIAZO COMPOUND AN AZO DYE HAVING A TONE SELECTED FROM THE CLASS CONSISTING OF YELLOW AND SEPIA TONES. 